Facile construction and biological imaging of cross-linked fluorescent organic nanoparticles with aggregation-induced emission feature through a catalyst-free azide-alkyne click reaction

The research in fluorescent organic nanoparticles (FONs) with aggregation-induced emission (AIE) feature shows an upward trend due to their outstanding optical properties and potential biomedical applications. In this work, a novel strategy has been developed for the first time through a catalyst-free azide-alkyne click reaction, which could directly conjugate azide containing polymers (PEGMA-AGE-N-3) and allcyne terminating AIE dye (named as PhE-OE) under mild experimental conditions. The final PEGMA-AGE-PhE copolymers containing AIE-active dye could self-assemble into FONs with intense fluorescence owing to their AIE feature. These PEGMA-AGE-PhE FONs were characterized by a series of characterization techniques in details. The cell viability as well as cell uptake behavior of PEGMA-AGE-PhE FONs was also examined to evaluate their potential for biomedical applications. We demonstrated that the catalyst-free azide-alkyne click reaction is effective for fabrication of AIE-active FONs and these AIE-active FONs showed high water dispersity and AIE feature. Moreover, the PEGMA-AGE-PhE FONs also exhibited low cytotoxicity and great potential for biological imaging. Taken together, a facile catalyst-free azide-alkyne click reaction with high efficiency has been developed for the preparation of AIE-active FONs, which showed excellent physicochemical properties for biological imaging applications. (C) 2017 Elsevier Ltd. All rights reserved.